Re: Academic Project

[Christian Leber <christian@leber.de>]

On Wed, Mar 04, 2009 at 01:24:46AM +0530, dinesh chandrasekaran wrote:
>    Can some one tell me how to go about achieving this.

First: I'm sorry, but i'm pretty sure that what you want to do... will
never work in a "normal" computer.
IMO the dom0 usually can access everything and all hardware, but it does
not matter as soon as it can access some hardware that can do DMA an
attacker may find an attack vector.

And i also don't see any application, why should the hypervisor be
trusted, but not the dom0?

>    How to allocate real memory (which is behind a PCI device) to guests?
>    I need to modify Xen source to achieve the above.

You want map memory from a PCI device in the address room?

That is no problem, despite that the maximum bar size (that will work on
many systems) is 256 MB (i have seen a single system were 1 GB was
working, probably there are others, no idea)
And by PIO reading you'll get like 10-20 MB/s or something like that.


Anyway (shameless plug) for such low level stuff i would not suggest to
use PCI, but a real interface like HyperTransport.

There is a HTX board, that offers advantages compared to a PCI board.
http://ra.ziti.uni-heidelberg.de/index.php?page=projects&id=htx


Christian